* WARNING: not thread-safe. */ public class DynamicChunk extends Chunk { private List

sections; // Key = ChunkUtils#getBlockIndex protected final Int2ObjectOpenHashMap entries = new Int2ObjectOpenHashMap<>(0); protected final Int2ObjectOpenHashMap tickableMap = new Int2ObjectOpenHashMap<>(0); private long lastChange; final CachedPacket chunkCache = new CachedPacket(this::createChunkPacket); final CachedPacket lightCache = new CachedPacket(this::createLightPacket); public DynamicChunk(@NotNull Instance instance, int chunkX, int chunkZ) { super(instance, chunkX, chunkZ, true); var sectionsTemp = new Section[maxSection - minSection]; Arrays.setAll(sectionsTemp, value -> new Section()); this.sections = List.of(sectionsTemp); } @Override public void setBlock(int x, int y, int z, @NotNull Block block) { assertLock(); this.lastChange = System.currentTimeMillis(); this.chunkCache.invalidate(); this.lightCache.invalidate(); // Update pathfinder if (columnarSpace != null) { final ColumnarOcclusionFieldList columnarOcclusionFieldList = columnarSpace.occlusionFields(); final var blockDescription = PFBlock.get(block); columnarOcclusionFieldList.onBlockChanged(x, y, z, blockDescription, 0); } Section section = getSectionAt(y); section.blockPalette() .set(toSectionRelativeCoordinate(x), toSectionRelativeCoordinate(y), toSectionRelativeCoordinate(z), block.stateId()); final int index = ChunkUtils.getBlockIndex(x, y, z); // Handler final BlockHandler handler = block.handler(); if (handler != null || block.hasNbt() || block.registry().isBlockEntity()) { this.entries.put(index, block); } else { this.entries.remove(index); } // Block tick if (handler != null && handler.isTickable()) { this.tickableMap.put(index, block); } else { this.tickableMap.remove(index); } } @Override public void setBiome(int x, int y, int z, @NotNull Biome biome) { assertLock(); this.chunkCache.invalidate(); Section section = getSectionAt(y); section.biomePalette().set( toSectionRelativeCoordinate(x) / 4, toSectionRelativeCoordinate(y) / 4, toSectionRelativeCoordinate(z) / 4, biome.id()); } @Override public @NotNull List

getSections() { return sections; } @Override public @NotNull Section getSection(int section) { return sections.get(section - minSection); } @Override public void tick(long time) { if (tickableMap.isEmpty()) return; tickableMap.int2ObjectEntrySet().fastForEach(entry -> { final int index = entry.getIntKey(); final Block block = entry.getValue(); final BlockHandler handler = block.handler(); if (handler == null) return; final Point blockPosition = ChunkUtils.getBlockPosition(index, chunkX, chunkZ); handler.tick(new BlockHandler.Tick(block, instance, blockPosition)); }); } @Override public @Nullable Block getBlock(int x, int y, int z, @NotNull Condition condition) { assertLock(); if (y < minSection * CHUNK_SECTION_SIZE || y >= maxSection * CHUNK_SECTION_SIZE) return Block.AIR; // Out of bounds // Verify if the block object is present if (condition != Condition.TYPE) { final Block entry = !entries.isEmpty() ? entries.get(ChunkUtils.getBlockIndex(x, y, z)) : null; if (entry != null || condition == Condition.CACHED) { return entry; } } // Retrieve the block from state id final Section section = getSectionAt(y); final int blockStateId = section.blockPalette() .get(toSectionRelativeCoordinate(x), toSectionRelativeCoordinate(y), toSectionRelativeCoordinate(z)); return Objects.requireNonNullElse(Block.fromStateId((short) blockStateId), Block.AIR); } @Override public @NotNull Biome getBiome(int x, int y, int z) { assertLock(); final Section section = getSectionAt(y); final int id = section.biomePalette() .get(toSectionRelativeCoordinate(x) / 4, toSectionRelativeCoordinate(y) / 4, toSectionRelativeCoordinate(z) / 4); return MinecraftServer.getBiomeManager().getById(id); } @Override public long getLastChangeTime() { return lastChange; } @Override public void sendChunk(@NotNull Player player) { if (!isLoaded()) return; player.sendPacket(chunkCache); } @Override public void sendChunk() { if (!isLoaded()) return; sendPacketToViewers(chunkCache); } @Override public @NotNull Chunk copy(@NotNull Instance instance, int chunkX, int chunkZ) { DynamicChunk dynamicChunk = new DynamicChunk(instance, chunkX, chunkZ); dynamicChunk.sections = sections.stream().map(Section::clone).toList(); dynamicChunk.entries.putAll(entries); return dynamicChunk; } @Override public void reset() { for (Section section : sections) section.clear(); this.entries.clear(); } private synchronized @NotNull ChunkDataPacket createChunkPacket() { final NBTCompound heightmapsNBT; // TODO: don't hardcode heightmaps // Heightmap { int dimensionHeight = getInstance().getDimensionType().getHeight(); int[] motionBlocking = new int[16 * 16]; int[] worldSurface = new int[16 * 16]; for (int x = 0; x < 16; x++) { for (int z = 0; z < 16; z++) { motionBlocking[x + z * 16] = 0; worldSurface[x + z * 16] = dimensionHeight - 1; } } final int bitsForHeight = MathUtils.bitsToRepresent(dimensionHeight); heightmapsNBT = NBT.Compound(Map.of( "MOTION_BLOCKING", NBT.LongArray(Utils.encodeBlocks(motionBlocking, bitsForHeight)), "WORLD_SURFACE", NBT.LongArray(Utils.encodeBlocks(worldSurface, bitsForHeight)))); } // Data final byte[] data = ObjectPool.PACKET_POOL.use(buffer -> { final BinaryWriter writer = new BinaryWriter(buffer); for (Section section : sections) writer.write(section); return writer.toByteArray(); }); return new ChunkDataPacket(chunkX, chunkZ, new ChunkData(heightmapsNBT, data, entries), createLightData()); } private synchronized @NotNull UpdateLightPacket createLightPacket() { return new UpdateLightPacket(chunkX, chunkZ, createLightData()); } private LightData createLightData() { BitSet skyMask = new BitSet(); BitSet blockMask = new BitSet(); BitSet emptySkyMask = new BitSet(); BitSet emptyBlockMask = new BitSet(); List skyLights = new ArrayList<>(); List blockLights = new ArrayList<>(); int index = 0; for (Section section : sections) { index++; final byte[] skyLight = section.getSkyLight(); final byte[] blockLight = section.getBlockLight(); if (skyLight.length != 0) { skyLights.add(skyLight); skyMask.set(index); } else { emptySkyMask.set(index); } if (blockLight.length != 0) { blockLights.add(blockLight); blockMask.set(index); } else { emptyBlockMask.set(index); } } return new LightData(true, skyMask, blockMask, emptySkyMask, emptyBlockMask, skyLights, blockLights); } @Override public @NotNull ChunkSnapshot updateSnapshot(@NotNull SnapshotUpdater updater) { Section[] clonedSections = new Section[sections.size()]; for (int i = 0; i < clonedSections.length; i++) clonedSections[i] = sections.get(i).clone(); var entities = instance.getEntityTracker().chunkEntities(chunkX, chunkZ, EntityTracker.Target.ENTITIES); final int[] entityIds = ArrayUtils.mapToIntArray(entities, Entity::getEntityId); return new SnapshotImpl.Chunk(minSection, chunkX, chunkZ, clonedSections, entries.clone(), entityIds, updater.reference(instance), tagHandler().readableCopy()); } private void assertLock() { assert Thread.holdsLock(this) : "Chunk must be locked before access"; } }